This invention generally relates to storage bags that have means for evacuation. In particular, the invention relates to evacuable storage bags that are reclosable by means a plastic zipper.
Reclosable plastic zippers are useful for sealing thermoplastic pouches or bags. Typically, the plastic zippers include a pair of interlockable fastener elements, or profiles, that form a closure. The profiles in plastic zippers can take on various configurations, e.g. interlocking rib and groove elements having so-called male and female profiles, interlocking alternating hook-shaped closure elements, etc.
For many packaged products, it is desirable to provide means for hermetically sealing the package. For example, it is known to provide a frangible hermetic seal in an unopened reclosable package that contains perishable material, such as foodstuff. However, once the frangible hermetic seal is broken and the package opened, the hermetic seal cannot be restored when the package is reclosed.
It is also known to store articles of manufacture, such as clothing, in evacuated storage bags having a reclosable zipper. In the case of reclosable storage bags that are evacuated after filling, it is desirable that the reclosed bag be hermetically sealed. Such a hermetic seal must be provided by the plastic zipper. Since it is desirable that such storage bags be reusable, it should be apparent that a one-time frangible hermetic seal is unsuitable. There is a need for an improved zipper design that can provide vacuum-tight sealing of an evacuable storage bag that can be reused many times.